1. The Field of the Invention
This invention relates to a constriction apparatus and method having application in the medical arts, and more particularly to an artificial sphincter capable of gently constricting a living tissue conduit to control the flow of biological materials therein without causing damage to living tissue of the conduit. Constriction of the living conduit is achieved in the apparatus and method of this invention through a combination of rotational and localized discrete radially compressive forces.
2. The Background Art
In the field of medical research and health care delivery, it is frequently necessary to clamp a living tissue conduit or otherwise stop the flow of biological materials (such as blood, urine, or stool) through such a conduit. Clamps which are well-known in the art generally involve two jaw members which transversely crimp the vessel to shut off the flow therein. It is also well known, however, that such vessels, have irregular wall thicknesses and corresponding irregularities in the inner wall surface. Thus a clamp having jaws which move with a parallel clamping action must clamp the vessel tightly enough to seal the thinnest portion of the irregular wall surface in order to prevent leakage past the clamp. Accordingly, if a conventional clamp of this type is used for a significant period of time, pressure necrosis of the underlying living tissue of the vessel results.
While many procedures have been adapted to alleviate this particular problem, it would be a significant advancement in the art to provide a constriction apparatus and method for gently constricting the flow of biological materials through a living tissue conduit which minimizes the changes of damaging the living tissue of such a vessel through pressure necrosis. Numerous applications call for a constricting movement, such as that present in a sphincter-type muscle, wherein muscular constriction radially narrows an open structure. Various other flow control devices could also benefit from axially oriented constricting movement.
A constriction or crimping apparatus disclosed in Falconer (U.S. Pat. No. 2,569,850) includes a plurality of rods mounted circumferentially around an axial opening parallel the axis thereof. A tube inserted in the opening is crimped by twisting the rods about the axis. Other constricting devices are shown in the patents of Colley (U.S. Pat. No. 2,434,835); Carlson, Jr. (U.S. Pat. No. 4,092,010); and Kingsford (U.S. Pat. No. 4,194,848). These devices, however, use entirely different operative mechanisms from that of the present invention.